A multiple-input multiple-output (“MIMO” for short) technology means that multiple transmit antennas are used at a transmit end device and multiple receive antennas are used at a receive end device, so that signals are transmitted by using the multiple antennas of the transmit end device and received by using the multiple antennas of the receive end device, thereby improving communication quality. By means of the MIMO technology, full use of spatial resources can be made, multiple output and multiple input are implemented by using multiple antennas, and a system channel capacity can be exponentially increased without increasing spectrum resources and transmit power of an antenna. With such obvious advantages, the MIMO technology is considered as a core technology of next-generation mobile communications.
Specifically, the transmit end device maps, onto the multiple antennas by means of space-time mapping, a data signal to be sent, to send the data signal. The receive end device performs space time decoding on signals received by using the antennas, so as to recover the data signal sent by the transmit end device.
With development and popularization of wireless communications technologies, service traffic of wireless communications sharply increases. How to improve efficiency in utilizing a limited quantity of receive antennas becomes an urgent problem to be resolved at present.